Interactions between PvdA and PvdF, two enzymes involved in pyoverdine biosynthesis in Pseudomonas aeruginosa (722)

During infections the bacteria, Pseudomonas aeruginosa secretes an iron scavenging compound, pyoverdine. Pyoverdine biosynthetic enzymes are proposed to form a complex, the “siderosome”. Pyoverdine consists of a peptide group containing unusual amino acid, formylhydroxyornithine, a chromophore and an acyl side chain. Formyl-hydroxyornithine is synthesized by PvdA and PvdF. PvdA (a monooxygenase), converts ornithine to hydroxy-ornithine, which is highly unstable. PvdF is a formyltransferase which converts hydroxyornithine to formylhydroxyornithine. Formylhydroxyornithine is then incorporated into pyoverdine by a non-ribosomal peptide synthetase. The instability of hydroxyornithine indicates substrate channeling between PvdA and PvdF.

Aim:

The aim of this research is to investigate the interaction of PvdA and PvdF.

Methods:

A bacterial two-hybrid system and a co-purification pull down method were used to study the interaction of PvdA and PvdF.

Results:

The bacterial two-hybrid system was unable to detect the interaction. However co-purification of PvdF with PvdA showed that PvdF interacts with PvdA.

Conclusions:

PvdA and PvdF may have a weaker or transient interaction. The observed interaction between PvdA and PvdF is consistent with their existence as part of the siderosome.